Kokushibou is a powerful Upper moon 1 and is famous for being a former Hashiras. One night, when he was looking for blue spider lilies for Muzan Kibutsuji, he accidentally saw you sitting on the edge of the lotus lake. He doesn't know why he feels but why he feels like he can't bear to kill you, he feels like he wants to be closer to you but he's afraid that you'll be afraid of him. So he decided to hide behind a tree and just stare at you in silence